$X$ -Band Circularly Polarized Electronically Steerable Parasitic Array Radiator of DRA

In this paper, an X-band electronically steerable parasitic array radiator (ESPAR) of circularly polarized dielectric resonator antennas (CP-DRAs) is proposed. The array consists of one driven CP-DRA coupled to four parasitic CP-DRAs. The parasitic elements are placed adopting a sequential rotation approach and are terminated by tunable varactors to steer the beam into the desired direction. The proposed CP-ESPAR technique eliminates the need of expensive phase shifters, which significantly reduces cost and fabrication complexity. For performance evaluation, a prototype of the proposed antenna is designed, fabricated, and measured. It is observed that the proposed antenna has a monotonic CP beam scanning from -22 to 22 operating at 10.5 GHz. In addition, the peak value of the realized gain is 6.6 dBic with 0.9 dB variation within the entire scanning range.